The invention relates to a shine-through lamp having a discharge chamber defined by a metal housing structure inside a closed lamp bulb and to its use in chemical analysis, in particular in combination with a VIS lamp.
These shine-through lamps lose their shine-through properties due to metal deposits in the lamp bulb in the region in front of the passage opening for visible light.
According to German published patent application DE 199 20 579 A1, in a known UV discharge lamp inside a discharge chamber containing a filling gas, electrodes are spaced apart from each other with a quartz disk. By means of boreholes in the electrodes, which overlap in a projection in the main irradiation direction, a shine-through lamp is created. In this way, a halogen lamp is arranged behind the deuterium lamp, such that its light passes through the two boreholes of the deuterium lamp electrodes, and the continuous UV spectrum of the deuterium lamp is expanded in the visible spectral range.
According to German Patent DE 196 28 925 B4, for increasing the usable radiation density, several diaphragms made of a high melting point material are arranged in a hydrogen discharge lamp, wherein diaphragms made of a high melting point ceramic are provided with an electrically conductive coating.
U.S. Pat. No. 6,870,317 B2 uses ceramic parts that limit the discharge in a gas discharge tube.
The commercially available shine-through lamps described according to the Heraeus brochure “Shine through deuterium lamps offering wide wavelength range in spectroscopy” have a metallic, open shield housing structure. This shield housing structure comprises several chambers in a box structure.
According to German published patent application DE 41 20 730 A1, a low pressure discharge lamp constructed as a shine-through lamp can also be constructed without electrodes.
European patent application publication no. EP 0 685 874 A1 discloses a deuterium discharge tube, in which the shield box structure has a discharge shielding plate and a support plate made of ceramic and a metallic front cover made of aluminum, which is mounted in front of the discharge shielding plate. The support plate has a convex cross section and a passage hole formed perpendicular to the support plate at its rear section. Metal pins are inserted into passage holes of the shielding plate and the support plate. Deposits of evaporated electrode material can lead to short circuits, which is why preventative measures are taken against these deposits.